1. Field of the Invention
The present invention relates to a connector plug having a following electrical radio frequency (RF) suppression filter comprising a metallic filter housing partially disposed onto the plug with electrical filter components, particularly inductances and capacitances, which are disposed within a filter housing, are embedded in a casting compound, are partially connected to the connector plug terminals at the power supply side and partially connected to the terminals facing the device to be energized, whereby the device-side terminals, particularly tabs, pigtails, pin plugs and the like, are conducted out at a partially open front end of the filter housing facing away from the connector plug and a protective connector extends over the full length of the RF suppression filter and is electrically connected to the filter housing.
2. Description of the Prior Art
Among other things, the RF suppression filters of the type generally set forth above are intended for use in desk-top computers, office machines and medical apparatus. The essential job of such a plug is to reduce the line-bound noise level. Since, due to their type of utilization, these filters are exposed in the environment of their use to high electrical and magnetic field strength levels, it must be provided that their noise suppression effect is not reduced by electrical and magnetic in-coupling onto the wiring or, respectively, the components of the filter circuit. These problems occur to a high degree particularly given their use in electrical devices having switched power supplies and/or in microprocessor systems having long bus lines. Insofar as attempts have already been made to resolve these problems, these are comprised, for example, in the utilization of metal housings for the RS suppression filters which are closed on all sides and which comprise insulated grommets for the leads. Deep-drawn housings of German silver or bipartite, tightly soldered housings of sheet iron thereby serve as metal housings.
Such filters have been disclosed, for example, as filters having an integrated rubber connector in which the leads extending from the commercial power supply side are carried out by way of this rubber connector, generally a socalled jack, and the contacting to the device which is provided with the filter is carried out by way of tabs, pigtails, solder lugs or the like. In this regard, see, for example, the technical information from the Components Division of Siemens AG, published by Siemens AG under the title "Elektromagnetische Vertraglichkeit durch den Einsatz von Entstorfiltern", order number B/2418, particularly Page 18 and the Siemens advertising brochure "Funk-Entstorfilter", delivery program 1980/81, pp. 12-13, obtainable under the order number B/2284.
The leads and carriers of the electrical components are thereby tightly glued in a half shell of German silver sheet. The electrical components in and of themselves in this RS suppression filter are mounted in the half shell, are isolated and soldered in manually. Proceeding from the opening side of the half shell, the electrical components are subsequently first fixed with a soft epoxy resin casting compound and are subsequently mechanically protected by a hard casting compound.
Instead of the German silver half shell, other commercially available RF suppression filters employ a deepdrawn German silver housing. The components are mounted in an auxiliary frame with flat plugs and soldered. The casting of the components and of the tab plug parts located in the filter housing occurs through a hole in the German silver housing which must be tightly connected to plug and frame by incorporating sealing rings. The casting hole is covered by a glued on type plate.
Other RF suppression filters commercially available utilize a soldered jacket tube of thin plate, whereby the electrical components are mounted on a carrier plate which is subsequently riveted to the plug. The soldering of the ground wire occurs through a hole in the jack tube which must be previously slipped onto the plug. The solder locations is covered by a type plate. The casting of the electronic components thereby occurs proceeding from the open rear side of the jacket tube.
Finally, RF suppression filters are known, for example, from the Siemens data book 1982/1984 "EMV Funk-Entstorung-Bauelemente, Filter", Page 240, which are distinguished by an effective magnetic shielding and good radio frequency properties, can be manufactured with relatively low expense and meet the national and international regulations for these filters. These filters have a filter housing comprising inductances and capacitances integrated into the housing and embedded in casting compound, and comprise electrical leads, particularly tabs, pigtails, pin plugs and the like, which extend out at open end fages of the filter housing and are connected to the electrical components. The filter housing is thereby lengthened such that the terminal elements facing outward of at least one lead are disposed shielded within the filter housing. For this purpose, the filter housing can, for example, be tapered shaft-like at its open end faces.
Although the manufacture of these filters is already possible with relatively little expense, it nonetheless requires manual activities, therefore, in part, solderings and involved winding operations which can only be manually executed.